Method and apparatus for reallocating pucch resource according to change of sps operation in wireless communication system

ABSTRACT

A user equipment (UE) receives, from a network, a semi-persistent scheduling (SPS) configuration and a physical uplink control channel (PUCCH) resource configuration. The PUCCH resource configuration may be included in the SPS configuration. When a change of an SPS operation is required, the user equipment transmits an SPS change request to the network and receives, from the network, an SPS resource grant activated according to the SPS change request. The user equipment changes allocation of a PUCCH resource allocated according to the PUCCH resource configuration, on the basis of the received SPS resource grant. For example, a timing at which or a period in which the PUCCH resource is allocated can be changed.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless communications, and, moreparticularly, to a method and apparatus for reallocating a physicaluplink control channel (PUCCH) resource according to change ofsemi-persistent scheduling (SPS) operation triggered by a user equipment(UE) in wireless communication system.

Related Art

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

LTE-based vehicle-to-everything (V2X) is urgently desired from marketrequirement as widely deployed LTE-based network provides theopportunity for the vehicle industry to realize the concept of‘connected cars’. The market for vehicle-to-vehicle (V2V) communicationin particular is time sensitive because related activities such asresearch projects, field test, and regulatory work are already ongoingor expected to start in some countries or regions such as US, Europe,Japan, Korea, and China.

Semi-persistent (SPS) is a function for considerably reducing a controlchannel overhead of an application which requires consistent wirelessresource allocation, such as voice over Internet protocol (VoIP). If theSPS is not given, every downlink (DL) or uplink (UL) physical resourceblock (PRB) allocation needs to be permitted through an access grantmessage on a physical downlink control channel (PDCCH). This issufficient for most of bursty best effort type applications having a bigpacket size, and thus, only a few users are usually scheduled in eachsubframe. However, in the case of an application which requiresconsistent allocation of a small packet (e.g. VoIP), an access grantoverhead of a control channel may be greatly reduced by the SPS. Thatis, the SPS introduces permanent RPB allocation which is expected by auser from the DL or which can be transmitted from the UL. There arevarious methods in which the SPS is able to set consistent allocation.

Since a message has a relatively small size and is periodicallytransmitted in V2X communication, a method for transmitting a V2Xmessage through a resource allocated by the SPS is being discussed.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for reallocating aphysical uplink control channel (PUCCH) resource according to change ofsemi-persistent scheduling (SPS) operation triggered by a user equipment(UE) in a wireless communication system.

In an aspect, a method for performing a semi-persistent scheduling (SPS)operation by a user equipment (UE) in a wireless communication system isprovided. The method includes receiving an SPS configuration and aphysical uplink control channel (PUCCH) resource configuration from anetwork, transmitting an SPS change request to the network, receiving anSPS resource grant activated based on the SPS change request from thenetwork, and changing allocation of a PUCCH resource, which has beenallocated by the PUCCH resource configuration, based on the received SPSresource grant.

In another aspect, a user equipment (UE) in a wireless communicationsystem is provided. The UE includes a memory, a transceiver, and aprocessor, operably coupled to the memory and the transceiver, thatcontrols the transceiver to receive an SPS configuration and a physicaluplink control channel (PUCCH) resource configuration from a network,controls the transceiver to transmit an SPS change request to thenetwork, controls the transceiver to receive an SPS resource grantactivated based on the SPS change request from the network, and changesallocation of a PUCCH resource, which has been allocated by the PUCCHresource configuration, based on the received SPS resource grant.

If an SPS resource is reallocated according to change of an SPSoperation triggered by a UE, a PUCCH resource can be reallocatedaccordingly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows LTE system architecture.

FIG. 2 shows a block diagram of a user plane protocol stack of an LTEsystem.

FIG. 3 shows a block diagram of a control plane protocol stack of an LTEsystem.

FIG. 4 shows reallocation of a PUCCH resource according to an embodimentof the present invention.

FIG. 5 shows reallocation of a PUCCH resource according to anotherembodiment of the present invention.

FIG. 6 shows reallocation of a PUCCH resource according to anotherembodiment of the present invention.

FIG. 7 shows a method of performing an SPS operation by an UE accordingto an embodiment of the present invention.

FIG. 8 shows a wireless communication system to implement an embodimentof the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The technology described below can be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), etc. The CDMA canbe implemented with a radio technology such as universal terrestrialradio access (UTRA) or CDMA-2000. The TDMA can be implemented with aradio technology such as global system for mobile communications(GSM)/general packet ratio service (GPRS)/enhanced data rate for GSMevolution (EDGE). The OFDMA can be implemented with a radio technologysuch as institute of electrical and electronics engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), etc.IEEE 802.16m is an evolution of IEEE 802.16e, and provides backwardcompatibility with an IEEE 802.16-based system. The UTRA is a part of auniversal mobile telecommunication system (UMTS). 3rd generationpartnership project (3GPP) long term evolution (LTE) is a part of anevolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTE uses the OFDMA indownlink and uses the SC-FDMA in uplink. LTE-advance (LTE-A) is anevolution of the 3GPP LTE.

For clarity, the following description will focus on the LTE-A. However,technical features of the present invention are not limited thereto.

FIG. 1 shows LTE system architecture. Referring to FIG. 1, the LTEsystem architecture includes one or more user equipment (UE; 10), anevolved-UMTS terrestrial radio access network (E-UTRAN) and an evolvedpacket core (EPC). The UE 10 refers to a communication equipment carriedby a user. The UE 10 may be fixed or mobile, and may be referred to asanother terminology, such as a mobile station (MS), a user terminal(UT), a subscriber station (SS), a wireless device, etc.

The E-UTRAN includes one or more evolved node-B (eNB) 20, and aplurality of UEs may be located in one cell. The eNB 20 provides an endpoint of a control plane and a user plane to the UE 10. The eNB 20 isgenerally a fixed station that communicates with the UE 10 and may bereferred to as another terminology, such as a base station (BS), anaccess point, etc. One eNB 20 may be deployed per cell.

Hereinafter, a downlink (DL) denotes communication from the eNB 20 tothe UE 10. An uplink (UL) denotes communication from the UE 10 to theeNB 20. A sidelink (SL) denotes communication between the UEs 10. In theDL, a transmitter may be a part of the eNB 20, and a receiver may be apart of the UE 10. In the UL, the transmitter may be a part of the UE10, and the receiver may be a part of the eNB 20. In the SL, thetransmitter and receiver may be a part of the UE 10.

The EPC includes a mobility management entity (MME) and a servinggateway (S-GW). The MME/S-GW 30 provides an end point of session andmobility management function for the UE 10. For convenience, MME/S-GW 30will be referred to herein simply as a “gateway,” but it is understoodthat this entity includes both the MME and S-GW. A packet data network(PDN) gateway (P-GW) may be connected to an external network.

The MME provides various functions including non-access stratum (NAS)signaling to eNBs 20, NAS signaling security, access stratum (AS)security control, inter core network (CN) node signaling for mobilitybetween 3GPP access networks, idle mode UE reachability (includingcontrol and execution of paging retransmission), tracking area listmanagement (for UE in idle and active mode), packet data network (PDN)gateway (P-GW) and S-GW selection, MME selection for handovers with MMEchange, serving GPRS support node (SGSN) selection for handovers to 2Gor 3G 3GPP access networks, roaming, authentication, bearer managementfunctions including dedicated bearer establishment, support for publicwarning system (PWS) (which includes earthquake and tsunami warningsystem (ETWS) and commercial mobile alert system (CMAS)) messagetransmission. The S-GW host provides assorted functions includingper-user based packet filtering (by e.g., deep packet inspection),lawful interception, UE Internet protocol (IP) address allocation,transport level packet marking in the DL, UL and DL service levelcharging, gating and rate enforcement, DL rate enforcement based onaccess point name aggregate maximum bit rate (APN-AMBR).

Interfaces for transmitting user traffic or control traffic may be used.The UE 10 is connected to the eNB 20 via a Uu interface. The UEs 10 areconnected to each other via a PC5 interface. The eNBs 20 are connectedto each other via an X2 interface. Neighboring eNBs may have a meshednetwork structure that has the X2 interface. The eNB 20 is connected tothe gateway 30 via an S1 interface.

FIG. 2 shows a block diagram of a user plane protocol stack of an LTEsystem. FIG. 3 shows a block diagram of a control plane protocol stackof an LTE system. Layers of a radio interface protocol between the UEand the E-UTRAN may be classified into a first layer (L1), a secondlayer (L2), and a third layer (L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system.

A physical (PHY) layer belongs to the L1. The PHY layer provides ahigher layer with an information transfer service through a physicalchannel. The PHY layer is connected to a medium access control (MAC)layer, which is a higher layer of the PHY layer, through a transportchannel. A physical channel is mapped to the transport channel. Databetween the MAC layer and the PHY layer is transferred through thetransport channel. Between different PHY layers, i.e., between a PHYlayer of a transmission side and a PHY layer of a reception side, datais transferred via the physical channel.

A MAC layer, a radio link control (RLC) layer, and a packet dataconvergence protocol (PDCP) layer belong to the L2. The MAC layerprovides services to the RLC layer, which is a higher layer of the MAClayer, via a logical channel. The MAC layer provides data transferservices on logical channels. The RLC layer supports the transmission ofdata with reliability. Meanwhile, a function of the RLC layer may beimplemented with a functional block inside the MAC layer. In this case,the RLC layer may not exist. The PDCP layer provides a function ofheader compression function that reduces unnecessary control informationsuch that data being transmitted by employing IP packets, such as IPv4or Ipv6, can be efficiently transmitted over a radio interface that hasa relatively small bandwidth.

A radio resource control (RRC) layer belongs to the L3. The RLC layer islocated at the lowest portion of the L3, and is only defined in thecontrol plane. The RRC layer controls logical channels, transportchannels, and physical channels in relation to the configuration,reconfiguration, and release of radio bearers (RBs). The RB signifies aservice provided the L2 for data transmission between the UE andE-UTRAN.

Referring to FIG. 2, the RLC and MAC layers (terminated in the eNB onthe network side) may perform functions such as scheduling, automaticrepeat request (ARQ), and hybrid ARQ (HARQ). The PDCP layer (terminatedin the eNB on the network side) may perform the user plane functionssuch as header compression, integrity protection, and ciphering.

Referring to FIG. 3, the RLC and MAC layers (terminated in the eNB onthe network side) may perform the same functions for the control plane.The RRC layer (terminated in the eNB on the network side) may performfunctions such as broadcasting, paging, RRC connection management, RBcontrol, mobility functions, and UE measurement reporting andcontrolling. The NAS control protocol (terminated in the MME of gatewayon the network side) may perform functions such as a SAE bearermanagement, authentication, LTE IDLE mobility handling, pagingorigination in LTE IDLE, and security control for the signaling betweenthe gateway and UE.

A physical channel transfers signaling and data between PHY layer of theUE and eNB with a radio resource. A physical channel consists of aplurality of subframes in time domain and a plurality of subcarriers infrequency domain. One subframe, which is 1 ms, consists of a pluralityof symbols in the time domain. Specific symbol(s) of the subframe, suchas the first symbol of the subframe, may be used for a physical downlinkcontrol channel (PDCCH). The PDCCH carries dynamic allocated resources,such as a physical resource block (PRB) and modulation and coding scheme(MCS).

A DL transport channel includes a broadcast channel (BCH) used fortransmitting system information, a paging channel (PCH) used for paginga UE, a downlink shared channel (DL-SCH) used for transmitting usertraffic or control signals, a multicast channel (MCH) used for multicastor broadcast service transmission. The DL-SCH supports HARQ, dynamiclink adaptation by varying the modulation, coding and transmit power,and both dynamic and semi-static resource allocation. The DL-SCH alsomay enable broadcast in the entire cell and the use of beamforming.

A UL transport channel includes a random access channel (RACH) normallyused for initial access to a cell, and an uplink shared channel (UL-SCH)for transmitting user traffic or control signals. The UL-SCH supportsHARQ and dynamic link adaptation by varying the transmit power andpotentially modulation and coding. The UL-SCH also may enable the use ofbeamforming.

The logical channels are classified into control channels fortransferring control plane information and traffic channels fortransferring user plane information, according to a type of transmittedinformation. That is, a set of logical channel types is defined fordifferent data transfer services offered by the MAC layer.

The control channels are used for transfer of control plane informationonly. The control channels provided by the MAC layer include a broadcastcontrol channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH) and adedicated control channel (DCCH). The BCCH is a downlink channel forbroadcasting system control information. The PCCH is a downlink channelthat transfers paging information and is used when the network does notknow the location cell of a UE. The CCCH is used by UEs having no RRCconnection with the network. The MCCH is a point-to-multipoint downlinkchannel used for transmitting multimedia broadcast multicast services(MBMS) control information from the network to a UE. The DCCH is apoint-to-point bi-directional channel used by UEs having an RRCconnection that transmits dedicated control information between a UE andthe network.

Traffic channels are used for the transfer of user plane informationonly. The traffic channels provided by the MAC layer include a dedicatedtraffic channel (DTCH) and a multicast traffic channel (MTCH). The DTCHis a point-to-point channel, dedicated to one UE for the transfer ofuser information and can exist in both UL and DL. The MTCH is apoint-to-multipoint downlink channel for transmitting traffic data fromthe network to the UE.

UL connections between logical channels and transport channels includethe DCCH that can be mapped to the UL-SCH, the DTCH that can be mappedto the UL-SCH and the CCCH that can be mapped to the UL-SCH. Downlinkconnections between logical channels and transport channels include theBCCH that can be mapped to the BCH or DL-SCH, the PCCH that can bemapped to the PCH, the DCCH that can be mapped to the DL-SCH, and theDTCH that can be mapped to the DL-SCH, the MCCH that can be mapped tothe MCH, and the MTCH that can be mapped to the MCH.

An RRC state indicates whether an RRC layer of the UE is logicallyconnected to an RRC layer of the E-UTRAN. The RRC state may be dividedinto two different states such as an RRC idle state (RRC_IDLE) and anRRC connected state (RRC_CONNECTED). In RRC_IDLE, the UE may receivebroadcasts of system information and paging information while the UEspecifies a discontinuous reception (DRX) configured by NAS, and the UEhas been allocated an identification (ID) which uniquely identifies theUE in a tracking area and may perform public land mobile network (PLMN)selection and cell re-selection. Also, in RRC_IDLE, no RRC context isstored in the eNB.

In RRC_CONNECTED, the UE has an E-UTRAN RRC connection and a context inthe E-UTRAN, such that transmitting and/or receiving data to/from theeNB becomes possible. Also, the UE can report channel qualityinformation and feedback information to the eNB. In RRC_CONNECTED, theE-UTRAN knows the cell to which the UE belongs. Therefore, the networkcan transmit and/or receive data to/from UE, the network can controlmobility (handover and inter-radio access technologies (RAT) cell changeorder to GSM EDGE radio access network (GERAN) with network assistedcell change (NACC)) of the UE, and the network can perform cellmeasurements for a neighboring cell.

In RRC_IDLE, the UE specifies the paging DRX cycle. Specifically, the UEmonitors a paging signal at a specific paging occasion of every UEspecific paging DRX cycle. The paging occasion is a time interval duringwhich a paging signal is transmitted. The UE has its own pagingoccasion. A paging message is transmitted over all cells belonging tothe same tracking area. If the UE moves from one tracking area (TA) toanother TA, the UE will send a tracking area update (TAU) message to thenetwork to update its location.

Sidelink is described. Sidelink is a UE to UE interface for sidelinkcommunication and sidelink discovery. The Sidelink corresponds to thePC5 interface. Sidelink communication is AS functionality enabling ProSedirect communication, between two or more nearby UEs, using E-UTRAtechnology but not traversing any network node. Sidelink discovery is ASfunctionality enabling ProSe direct discovery, using E-UTRA technologybut not traversing any network node. Sidelink uses UL resources andphysical channel structure similar to UL transmissions. Sidelinktransmission uses the same basic transmission scheme as the ULtransmission scheme. However, sidelink is limited to single clustertransmissions for all the sidelink physical channels. Further, sidelinkuses a 1 symbol gap at the end of each sidelink subframe.

Sidelink communication is a mode of communication whereby UEs cancommunicate with each other directly over the PC5 interface. Thiscommunication mode is supported when the UE is served by E-UTRAN andwhen the UE is outside of E-UTRA coverage. Only those UEs authorized tobe used for public safety operation can perform sidelink communication.

In order to perform synchronization for out of coverage operation, UE(s)may act as a synchronization source by transmitting SBCCH and asynchronization signal. SBCCH carries the most essential systeminformation needed to receive other sidelink channels and signals. SBCCHalong with a synchronization signal is transmitted with a fixedperiodicity of 40 ms. When the UE is in network coverage, the contentsof SBCCH are derived from the parameters signaled by the eNB. When theUE is out of coverage, if the UE selects another UE as a synchronizationreference, then the content of SBCCH is derived from the received SBCCH.Otherwise, UE uses pre-configured parameters. System information blocktype-18 (SIB18) provides the resource information for synchronizationsignal and SBCCH transmission. There are two pre-configured subframesevery 40 ms for out of coverage operation. UE receives synchronizationsignal and SBCCH in one subframe and transmit synchronization signal andSBCCH on another subframe if UE becomes synchronization source based ondefined criterion.

UE performs sidelink communication on subframes defined over theduration of sidelink control period. The sidelink control period is theperiod over which resources allocated in a cell for sidelink controlinformation and sidelink data transmissions occur. Within the sidelinkcontrol period, the UE sends sidelink control information followed bysidelink data. Sidelink control information indicates a Layer 1 ID andcharacteristics of the transmissions (e.g. MCS, location of theresource(s) over the duration of sidelink control period, timingalignment).

The UE performs transmission and reception over Uu and PC5 with thefollowing decreasing priority order:

-   -   Uu transmission/reception (highest priority);    -   PC5 sidelink communication transmission/reception;    -   PC5 sidelink discovery announcement/monitoring (lowest        priority).

The UE supporting sidelink communication can operate in two modes forresource allocation. The first mode is a scheduled resource allocation.The scheduled resource allocation may be referred to as Mode 1. In Mode1, the UE needs to be RRC_CONNECTED in order to transmit data. The UErequests transmission resources from the eNB. The eNB schedulestransmission resources for transmission of sidelink control informationand data. The UE sends a scheduling request (dedicated schedulingrequest (D-SR) or random access) to the eNB followed by a sidelinkbuffer status report (BSR). Based on the sidelink BSR, the eNB candetermine that the UE has data for a sidelink communication transmissionand estimate the resources needed for transmission. The eNB can scheduletransmission resources for sidelink communication using configuredsidelink radio network temporary identity (SL-RNTI).

The second mode is a UE autonomous resource selection. The UE autonomousresource selection may be referred to as Mode 2. In Mode 2, a UE on itsown selects resources from resource pools and performs transport formatselection to transmit sidelink control information and data. There canbe up to 8 transmission pools either pre-configured for out of coverageoperation or provided by RRC signalling for in-coverage operation. Eachpool can have one or more ProSe per-packet-priority (PPPP) associatedwith it. For transmission of a MAC protocol data unit (PDU), UE selectsa transmission pool in which one of the associated PPPP is equal to thePPPP of a logical channel with highest PPPP among the logical channelidentified in the MAC PDU. There is one to one association betweensidelink control pool and sidelink data pool. Once the resource pool isselected, the selection is valid for the entire sidelink control period.After the sidelink control period is finished, the UE may performresource pool selection again.

A set of transmission and reception resource pools for sidelink controlinformation when the UE is out of coverage for sidelink communication ispre-configured in the UE. The resource pools for sidelink controlinformation when the UE is in coverage for sidelink communication areconfigured as below. The resource pools used for reception areconfigured by the eNB via RRC, in broadcast signaling. The resource poolused for transmission is configured by the eNB via RRC, in dedicated orbroadcast signaling, if Mode 2 is used, and the resource pool used fortransmission is configured by the eNB via RRC, in dedicated signaling ifMode 1 is used. The eNB schedules the specific resource(s) for sidelinkcontrol information transmission within the configured reception pools.

A set of transmission and reception resource pools for data when the UEis out of coverage for sidelink communication is pre-configured in theUE. The resource pools for data when the UE is in coverage for sidelinkcommunication are configured as below. The resource pools used fortransmission and reception are configured by the eNB via RRC, indedicated or broadcast signaling, if Mode 2 is used. There is noresource pool for transmission and reception if Mode 1 is used.

Sidelink discovery is defined as the procedure used by the UE supportingsidelink discovery to discover other UE(s) in its proximity, usingE-UTRA direct radio signals via PC5. Sidelink discovery is supportedboth when UE is served by EUTRAN and when UE is out of EUTRA coverage.Only ProSe-enabled public safety UE can perform sidelink discovery whenit is out of EUTRA coverage. For public safety sidelink discovery, theallowed frequency is pre-configured in the UE, and is used even when UEis out of coverage of EUTRA in that frequency. The pre-configuredfrequency is the same frequency as the public safety ProSe carrier.

In order to perform synchronization, UE(s) participating in announcingof discovery messages may act as a synchronization source bytransmitting a synchronization signal based on the resource informationfor synchronization signals provided in SIB19.

There are two types of resource allocation for discovery messageannouncement. The first type is UE autonomous resource selection whichis a resource allocation procedure where resources for announcing ofdiscovery message are allocated on a non UE specific basis. The UEautonomous resource selection may be referred to as Type 1. In Type 1,the eNB provides the UE(s) with the resource pool configuration used forannouncing of discovery message. The configuration may be signaled inbroadcast or dedicated signaling. The UE autonomously selects radioresource(s) from the indicated resource pool and announces discoverymessage. The UE can announce discovery message on a randomly selecteddiscovery resource during each discovery period.

The second type is scheduled resource allocation which is a resourceallocation procedure where resources for announcing of discovery messageare allocated on per UE specific basis. The scheduled resourceallocation may be referred to as Type 2. In Type 2, the UE inRRC_CONNECTED may request resource(s) for announcing of discoverymessage from the eNB via RRC. The eNB assigns resource(s) via RRC. Theresources are allocated within the resource pool that is configured inUEs for announcement.

For UEs in RRC_IDLE, the eNB may select one of the following options.The eNB may provide a resource pool for UE autonomous resource selectionbased discovery message announcement in SIB19. UEs that are authorizedfor sidelink discovery use these resources for announcing discoverymessage in RRC_IDLE. Or, the eNB may indicate in SIB19 that it supportssidelink discovery but does not provide resources for discovery messageannouncement. UEs need to enter RRC_CONNECTED in order to requestresources for discovery message announcement.

For UEs in RRC_CONNECTED, a UE authorized to perform sidelink discoveryannouncement indicates to the eNB that it wants to perform sidelinkdiscovery announcement. UE can also indicate to the eNB, thefrequency(s) in which sidelink discovery announcement is desired. TheeNB validates whether the UE is authorized for sidelink discoveryannouncement using the UE context received from MME. The eNB mayconfigure the UE with resource pool for UE autonomous resource selectionfor discovery message announcement via dedicated signaling. The eNB mayconfigure resource pool along with dedicated resource in the form oftime and frequency indices for discovery message announcement viadedicated RRC signaling. The resources allocated by the eNB viadedicated signaling are valid until the eNB re-configures theresource(s) by RRC signaling or the UE enters RRC_IDLE.

Authorized receiving UEs in RRC_IDLE and RRC_CONNECTED monitor resourcepools used for UE autonomous resource selection and resource pools forscheduled resource allocation. The eNB provides the resource poolconfiguration used for discovery message monitoring on intra frequency,inter frequency of same or different PLMNs cells in RRC signaling (SIB19or dedicated). The RRC signaling (SIB19 or dedicated) may containdetailed sidelink discovery configuration used for announcement ofsidelink discovering in cells of intra-frequency, inter-frequency ofsame or different PLMNs.

Semi-persistent scheduling (SPS) is described. It may be referred to as3GPP TS 36.300 V13.2.0 (2015 December) Section 11.1.1, 11.1.2 and 3GPPTS 36.321 V13.0.0 (2015 December) Section 5.10. E-UTRAN can allocatesemi-persistent DL resources for the first HARQ transmissions to UEs.RRC defines the periodicity of the semi-persistent DL grant. PDCCHindicates whether the DL grant is a semi-persistent one, i.e. whether itcan be implicitly reused in the following TTIs according to theperiodicity defined by RRC.

When required, retransmissions are explicitly signaled via the PDCCH(s).In the subframes where the UE has semi-persistent DL resource, if the UEcannot find its cell radio network temporary identity (C-RNTI) on thePDCCH(s), a DL transmission according to the semi-persistent allocationthat the UE has been assigned in the TTI is assumed. Otherwise, in thesubframes where the UE has semi-persistent DL resource, if the UE findsits C-RNTI on the PDCCH(s), the PDCCH allocation overrides thesemi-persistent allocation for that TTI and the UE does not decode thesemi-persistent resources.

When carrier aggregation (CA) is configured, semi-persistent DLresources can only be configured for the primary cell (PCell) and onlyPDCCH allocations for the PCell can override the semi-persistentallocation. When dual connectivity (DC) is configured, semi-persistentDL resources can only be configured for the PCell or primary secondarycell (PSCell). Only PDCCH allocations for the PCell can override thesemi-persistent allocation for PCell and only PDCCH allocations for thePSCell can override the semi-persistent allocation for PSCell.

In addition, E-UTRAN can allocate a semi-persistent UL resource for thefirst HARQ transmissions and potentially retransmissions to UEs. RRCdefines the periodicity of the semi-persistent UL grant. PDCCH indicateswhether the UL grant is a semi-persistent one, i.e. whether it can beimplicitly reused in the following TTIs according to the periodicitydefined by RRC.

In the subframes where the UE has semi-persistent UL resource, if the UEcannot find its C-RNTI on the PDCCH(s), a UL transmission according tothe semi-persistent allocation that the UE has been assigned in the TTIcan be made. The network performs decoding of the pre-defined PRBsaccording to the pre-defined MCS. Otherwise, in the subframes where theUE has semi-persistent UL resource, if the UE finds its C-RNTI on thePDCCH(s), the PDCCH allocation overrides the persistent allocation forthat TTI and the UE's transmission follows the PDCCH allocation, not thesemi-persistent allocation. Retransmissions are either implicitlyallocated in which case the UE uses the semi-persistent UL allocation,or explicitly allocated via PDCCH(s) in which case the UE does notfollow the semi-persistent allocation.

Similarly as for the DL, semi-persistent UL resources can only beconfigured for the PCell and only PDCCH allocations for the PCell canoverride the semi-persistent allocation. When DC is configured,semi-persistent UL resources can only be configured for the PCell orPSCell. Only PDCCH allocations for the PCell can override thesemi-persistent allocation for PCell and only PDCCH allocations for thePSCell can override the semi-persistent allocation for PSCell.

When SPS is enabled by RRC, the following information is provided:

-   -   SPS C-RNTI;    -   UL SPS interval semiPersistSchedIntervalUL and number of empty        transmissions before implicit release implicitReleaseAfter, if        SPS is enabled for the UL;    -   Whether twoIntervalsConfig is enabled or disabled for UL, only        for time division duplex (TDD);    -   DL SPS interval semiPersistSchedIntervalDL and number of        configured HARQ processes for SPS numberOfConjSPS-Processes, if        SPS is enabled for the DL;

When SPS for UL or DL is disabled by RRC, the corresponding configuredgrant or configured assignment shall be discarded.

The above information may be carried in SPS-Config information element(IE). The IE SPS-Config is used to specify the SPS configuration. Table1 shows the SPS-Config IE.

TABLE 1 -- ASN1START SPS-Config ::= SEQUENCE { semiPersistSchedC-RNTIC-RNTI  OPTIONAL, -- Need OR sps-ConfigDL SPS-ConfigDL  OPTIONAL, --Need ON sps-ConfigUL SPS-ConfigUL  OPTIONAL -- Need ON } SPS-ConfigDL::= CHOICE{ release NULL, setup  SEQUENCE { semiPersistSchedIntervalDLENUMERATED {  sf10, sf20, sf32, sf40, sf64, sf80,  sf128, sf160, sf320,sf640, spare6,  spare5, spare4, spare3, spare2,  spare1},numberOfConfSPS-Processes INTEGER (1..8), n1PUCCH-AN-PersistentListN1PUCCH-AN-PersistentList, ..., [[ twoAntennaPortActivated-r10 CHOICE {release NULL, setup SEQUENCE { n1PUCCH-AN-PersistentListP1-r10 N1PUCCH-AN-PersistentList  } } OPTIONAL -- Need ON ]] } } SPS-ConfigUL::= CHOICE { release NULL, setup SEQUENCE { semiPersistSchedIntervalULENUMERATED { sf10, sf20, sf32, sf40, sf64, sf80, sf128, sf160, sf320,sf640, spare6, spare5, spare4, spare3, spare2, spare1},implicitReleaseAfter ENUMERATED {e2, e3, e4, e8}, p0-Persistent SEQUENCE{ p0-NominalPUSCH-Persistent INTEGER (−126..24), p0-UE-PUSCH-PersistentINTEGER (−8..7) }  OPTIONAL, -- Need OP twoIntervalsConfig ENUMERATED{true} OPTIONAL, -- Cond TDD ...,  [[ p0-PersistentSubframeSet2-r12CHOICE { release NULL, setup SEQUENCE {p0-NominalPUSCH-PersistentSubframeSet2-r12 INTEGER (−126..24),p0-UE-PUSCH-PersistentSubframeSet2-r12 INTEGER (−8..7) } } OPTIONAL --Need ON ]] } } N1PUCCH-AN-PersistentList ::= SEQUENCE (SIZE (1..4)) OFINTEGER (0..2047) -- ASN1STOP

As described above, the SPS-Config IE may include at least one of SPSC-RNTI (semiPersistSchedC-RNTI), UL SPS interval(semiPersistSchedIntervalUL) and number of empty transmissions beforeimplicit release (implicitReleaseAfter), whether twoIntervalsConfig isenabled or disabled for UL (twoIntervalsConfig), and DL SPS interval(semiPersistSchedIntervalDL) and number of configured HARQ processes forSPS (numberOfConfSPS-Processes), if SPS is enabled for the DL.

After a SPS DL assignment is configured, the MAC entity shall considersequentially that the N^(th) assignment occurs in the subframe forwhich:

(10*SFN+subframe)=[(10*SFN_(start time)+subframe_(start time))+N*semiPersistSchedIntervalDL]modulo 10240,

where SFN_(start time) and subframe_(start time) are the system framenumber (SFN) and subframe, respectively, at the time the configured DLassignment were (re-) initialized.

After a SPS UL grant is configured, the MAC entity shall:

1> if twoIntervalsConfig is enabled by upper layer:

2> set the Subframe_Offset according to Table 3 below.

TABLE 3 TDD UL/DL Position of initial Semi-Persistent Subframe_Offsetconfiguration grant value (ms) 0 N/A 0 1 Subframes 2 and 7 1 Subframes 3and 8 −1 2 Subframe 2 5 Subframe 7 −5 3 Subframes 2 and 3 1 Subframe 4−2 4 Subframe 2 1 Subframe 3 −1 5 N/A 0 6 N/A 0

1> else:

2> set Subframe_Offset to 0.

1> consider sequentially that the N^(th) grant occurs in the subframefor which:

(10*SFN+subframe)=[(10*SFN_(start time)+subframe_(start time))+N*semiPersistSchedIntervalUL+Subframe_Offset*(Nmodulo 2)] modulo 10240,  2>

where SFN_(start time) and subframe_(start time) are the SFN andsubframe, respectively, at the time the configured uplink grant were(re-)initialized.

The MAC entity shall clear the configured UL grant immediately afterimplicitReleaseAfter number of consecutive new MAC PDUs each containingzero MAC SDUs have been provided by the multiplexing and assemblyentity, on the SPS resource.

Vehicle-to-everything (V2X) communication is described. V2Xcommunication contains the three different types, i.e.vehicle-to-vehicle (V2V) communications, vehicle-to-infrastructure (V2I)communications, and vehicle-to-pedestrian (V2P) communications. Thesethree types of V2X can use “co-operative awareness” to provide moreintelligent services for end-users. This means that transport entities,such as vehicles, road side unit (RSU), and pedestrians, can collectknowledge of their local environment (e.g. information received fromother vehicles or sensor equipment in proximity) to process and sharethat knowledge in order to provide more intelligent services, such ascooperative collision warning or autonomous driving.

V2X service is a type of communication service that involves atransmitting or receiving UE using V2V application via 3GPP transport.Based on the other party involved in the communication, it can befurther divided into V2V service, V2I service, V2P service, andvehicle-to-network (V2N) service. V2V service is a type of V2X service,where both parties of the communication are UEs using V2V application.V2I service is a type of V2X service, where one party is a UE and theother party is an RSU both using V2I application. The RSU is an entitysupporting V2I service that can transmit to, and receive from a UE usingV2I application. RSU is implemented in an eNB or a stationary UE. V2Pservice is a type of V2X service, where both parties of thecommunication are UEs using V2P application. V2N service is a type ofV2X service, where one party is a UE and the other party is a servingentity, both using V2N applications and communicating with each othervia LTE network entities.

In V2V, E-UTRAN allows such UEs that are in proximity of each other toexchange V2V-related information using E-UTRA(N) when permission,authorization and proximity criteria are fulfilled. The proximitycriteria can be configured by the mobile network operator (MNO).However, UEs supporting V2V service can exchange such information whenserved by or not served by E-UTRAN which supports V2X service. The UEsupporting V2V applications transmits application layer information(e.g. about its location, dynamics, and attributes as part of the V2Vservice). The V2V payload must be flexible in order to accommodatedifferent information contents, and the information can be transmittedperiodically according to a configuration provided by the MNO. V2V ispredominantly broadcast-based. V2V includes the exchange of V2V-relatedapplication information between distinct UEs directly and/or, due to thelimited direct communication range of V2V, the exchange of V2V-relatedapplication information between distinct UEs via infrastructuresupporting V2X Service, e.g., RSU, application server, etc.

In V2I, the UE supporting V2I applications sends application layerinformation to RSU. RSU sends application layer information to a groupof UEs or a UE supporting V2I applications.

In V2P, E-UTRAN allows such UEs that are in proximity of each other toexchange V2P-related information using E-UTRAN when permission,authorization and proximity criteria are fulfilled. The proximitycriteria can be configured by the MNO. However, UEs supporting V2Pservice can exchange such information even when not served by E-UTRANwhich supports V2X service. The UE supporting V2P applications transmitsapplication layer information. Such information can be broadcast by avehicle with UE supporting V2X Service (e.g. warning to pedestrian),and/or by a pedestrian with UE supporting V2X Service (e.g. warning tovehicle). V2P includes the exchange of V2P-related applicationinformation between distinct UEs (one for vehicle and the other forpedestrian) directly and/or, due to the limited direct communicationrange of V2P, the exchange of V2P-related application informationbetween distinct UEs via infrastructure supporting V2X service, e.g.,RSU, application server, etc.

In V2X communication, messages such as common awareness messages (CAM),decentralized environmental notification messages (DENM), or basicsafety messages (BSM) may be transmitted. The CAM includes informationon a vehicle's type, a location, speed, a direction, etc., and may beperiodically broadcasted by any vehicle. The DENM includes informationon a type of a particular event and an area where the particular eventhas occurred, and may be broadcasted by an RSU or a vehicle. The BSM isincluded in the U.S. J2735 basic safety message, and have similarcharacteristics to those of the CAM. Through the BSM, an emergency brakewarning, a front collision warning, an intersection safety support, ablind spot and line departure warning, a overtake warning, anout-of-control warning service may be provided.

Hereinafter, according to an embodiment of the present invention, amethod for reallocating a PUCCH resource according to adjustment of SPSconfiguration is described. When performing V2X communication using theSPS, a UE is able to trigger an SPS change request from an eNB in manycases. For example, the CAM may be periodically generated in a periodthat is dynamically changed between 1s and 100 ms, and a generating timeof the CAM may be dynamically changed. In this case, when it isnecessary to change an SPS resource in response to the change of thegenerating time of the CAM, the UE may trigger an SPS change requestfrom the eNB. Alternatively, when the CAM generating period is changedfrom 1s to 100 ms, allocating the SPS resource for is cannot match withthe changed generating time of the CAM. In this case, by consideringdynamic CAM generation according to time, the eNB may provide the UEwith a plurality of SPS configurations which covers the dynamic changeof the CAM generating period, and, when it is necessary to change theSPS resources according to the change of the CAM generating period, theUE may trigger an SPS change request from the eNB.

As such, when the SPS operation change is triggered by the UE, the eNBmay reallocate periodic generation of a PUCCH resource. The PUCCHresource may be reallocated according to PUCCH resource configuration.The PUCCH resource configuration may be included as a part of the SPSconfiguration. Thus, when the UE triggers an SPS change request inresponse to change of message generating time or change of a messagegenerating period and the eNB resumes or reactivates an SPS resourcegrant, the UE may change allocation of the PUCCH resource. For example,when a timing of an SPS resource of a physical uplink shared channel(PUSCH), which delivers UL data, or a physical sidelink shared channel(PSSCH), which delivers SL data, is changed due to reactivation of theSPS, a timing of the PUCCH resource may be also changed and allocated.In another example, if an SPS period on a PUSCH or a PSSCH is changed asone SPS configuration is reselected from among a plurality of SPSconfigurations, a period of the PUSCCH resource (e.g. a period of ascheduling request (SR) to be transmitted through the PUCCH) may be alsochanged to fit the reselected SPS configuration.

Alternatively, a part of the PUCCH resource configuration may beimplicit. That is, periodic generation of a PUCCH resource may bereallocated by an implicit rule. For example, a timing of the PUCCHresource may be derived from a timing of an UL/SL data transmission oran activation message. For example, the PUCCH resource may be allocatedx subframe before a timing of the allocated UL/SL data resource.Alternatively, the PUCCH resource may be always allocated y subframeafter a timing of an activation message. In this case, the other part ofthe PUCCH resource configuration may be explicit. For example, afrequency resource position may be explicitly included in the PUCCHresource configuration.

If the PUCCH resource configuration is a part of the SPS configuration,a plurality of SPS configurations may include each PUCCH resourceconfiguration, respectively. When a plurality of SPS configurations isallocated and a UE and an eNB changes to the new SPS configuration, theUE and the eNB change to a new PUCCH resource allocation correspondingto the new SPS configuration.

FIG. 4 shows reallocation of a PUCCH resource according to an embodimentof the present invention.

In step S100, the eNB transmits SPS configuration for a CAM to the eNB.

In step S110, a CAM is generated, a CAM generating period is assumed tobe 1s. The eNB configures a PDCCH to be addressed to SPS C-RNTI #1 instep S111, and, in step S112, and transmits SPS activation through thecorresponding PDCCH to the UE. Having received the SPS activation, theUE transmits the CAM through a UL (PUSCH) or an SL (PUSCH) using an SPSresource. The SPS period is assumed to be 1s.

In step S115, a PUCCH is configured. A resource for the PUCCH may beexplicitly allocated from the PUCCH resource configuration.Alternatively, the resource for the PUCCH may be implicitly allocated.For example, the resource for the PUCCH may be allocated x subframebefore the SPS resource. The PUCCH resource is allocated in step S115,but it is assumed that the PUCCH is not actually transmitted.

In step S120, the CAM generating time is changed. Accordingly, in stepS121, the UE transmits an SPS change request to the eNB. The eNBconfigures a PDCCH to be addressed to SPS C-RNTI #1 in step S122, andtransmits SPS reactivation to the UE through the corresponding PDCCH instep S123. Having received the SPS reactivation, the UE transmits theCAM through an UL or an SL using the SPS resource in step S124.

In step S125, a PUCCH is configured. A resource for the PUCCH may beexplicitly allocated from PUCCH resource configuration. Alternatively,the resource for the PUCCH may be implicitly allocated. For example, theresource for the PUCCH may be allocated x subframe before the SPSresource of step S114. When a timing of an SPS resource of PUSCH orPSSCH is changed in response to SPS reactivation, a timing of the PUCCHresource is also changed to fit the timing of the SPS resource. In stepS124, the timing of the SPS resource is advanced, and thus, the timingof the PUCCH resource is also advanced accordingly. In step S125, thePUCCH resource is allocated, and a PUCCH is transmitted using thecorresponding PUCCH resource. An SPS change request of step S121 may betransmitted using the changed PUCCH resource.

FIG. 5 shows reallocation of a PUCCH resource according to anotherembodiment of the present invention.

In step S200, an eNB transmits three SPS configurations for a CAM to aUE. It is assumed that a first SPS configuration supports an SPSresource of a first period, a second SPS configuration supports an SPSresource of a second period, and a third SPS configuration supports anSPS resource of a third period. In this embodiment, it is assumed to bethat the first period is 1s, the second period is 500 ms, and the thirdperiod is 100 ms.

In S210, a CAM is generated. A CAM generating period is assumed to be1s. In step S211, a UE transmits an SPS change request to an eNB. TheeNB configures a PDCCH to be addressed to SPS C-RNTI #1 in step S212,and transmits SPS activation to the UE through the corresponding toPDCCH in step S213. Having received the SPS activation, the UE transmitsthe CAM through an UL or an SL using an SPS resource according to thefirst SPS configuration in step S214. According to the first SPSconfiguration which supports the first period, the CAM may betransmitted every 1s.

In step S215, a PUCCH is configured. A resource for the PUCCH may beexplicitly allocated from a PUCCH resource configuration. A PUCCHresource may be included in the first SPS configuration. Alternatively,the resource for the PUCCH may be allocated implicitly. For example, thePUCCH resource may be allocated x subframe before from the SPS resourceof step S214. In step S215, the PUCCH resource is allocated but it isassumed that a PUCCH is not actually transmitted.

In step S220, a CAM generating time/period is changed. It is assumedthat the CAM generating period is shorter than 1s. In step S221, the UEtransmits an SPS change request to the eNB. The eNB configures a PDCCHto be addressed to SPS C-RNTI #3 in step S222, and transmits SPS releaseof the first SPS configuration and SPS activation of the third SPSconfiguration to the UE through the corresponding PDCCH. Having receivedthe SPS activation of the third SPS configuration, the UE transmits theCAM through an UL or an SL using an SPS resource according to the thirdSPS configuration in S224. According to the third SPS configurationwhich supports the third period, the CAM may be transmitted every 100ms.

In step S225, a PUCCH is configured. A resource for the PUCCH may beexplicitly configured from a PUCCH resource configuration. The PUCCHresource configuration may be included in the third SPS configuration.Alternatively the resource for the PUCCH may be implicitly allocated.For example, the resource for the PUCCH may be allocated x subframebefore the SPS resource of step S224. When a SPS period on the PUSCH orthe PSSCH is changed due to activation of the third SPS configuration,even a period of the PUCCH resource is changed to fit a period of theSPS resource. As the period of the SPS resource is reduced in step S224,even the period of the PUCCH resource is reduced accordingly. In stepS225, the PUCCH resource is allocated, and the PUCCH is transmittedusing the corresponding PUCCH resource.

In step S226, whenever there is not data to be transmitted in aparticular SPS resource grant, the UE transmits an NACK in response tothe SPS resource grant using the corresponding PUCCH resource. At thispoint, a plurality of NACKs may be continuously transmitted in responseto different SPS resource grants. When the plurality of NACKs iscontinuously transmitted, the CAM generating period may be changed intoa greater value in step S230. In step S231, the UE may transmit an SPSchange request to the eNB. The eNB configures a PDCCH to be addressed toSPS C-RNTI #2 in step S232, and transits SPS release of the third SPSconfiguration and SPS activation of the second SPS configuration throughthe corresponding PDCCH in step S233. Having received the SPS activationof the second SPS configuration, the UE transmits the CAM through an ULor an SL using an SPS resource according to the second SPS configurationin step S234. According to the second configuration which supports thesecond period, the CAM may be transmitted every 500 ms.

FIG. 6 shows reallocation of a PUCCH resource according to anotherembodiment of the present invention.

In step S300, an eNB transmits three SPS configurations for a CAM to aUE. It is assumed that a first SPS configuration supports an SPSresource of a first period, a second SPS configuration supports an SPSresource of a second period, and a third SPS configuration supports anSPS resource of a third period. In this embodiment, it is assumed thatthe first period is 1s, the second period is 500 ms, and the thirdperiod is 100 ms.

In step S310, a CAM is generated. A CAM generating period is assumed tobe 1s. In S311, a UE transmits an SPS change request to an eNB. The eNBconfigures a PDCCH to be addressed to SPS C-RNTI #1 in step S312, andtransmits SPS activation through the corresponding PDCCH to the UE instep S313. Having received the SPS activation, the UE transmits througha UL or an SL using an SPS resource according to the first SPSconfiguration in step S314. According to the first SPS configurationwhich supports the first period, the CAM may be transmitted every 1s.

In step S315, a PUCCH is configured. A resource for the PUCCH may beexplicitly allocated from a PUCCH resource configuration. The PUCCHresource may be included in the first SPS configuration. Alternatively,the resource for the PUCCH may be implicitly allocated. For example, theresource for the PUCCH may be allocated x subframe before the SPSresource of step S314. In step S315, the PUCCH resource is allocated butit is assumed that the PUCCH is not actually transmitted.

In step S320, a CAM generating time/period is changed. It is assumedthat the CAM generating period is reduced to be shorter than 1s. In stepS321, a UE transmits an SPS change request to an eNB. The eNB configuresa PDCCH to be addressed to SPS C-RNTI #3 in step S322, and transmits SPSrelease of the first SPS configuration and SPS activation of the thirdSPS configuration through the corresponding PDCCH in step S323. Havingreceived the SPS activation of the third SPS configuration, the UEtransmits the CAM through an UL or an SL using an SPS resource accordingto the third SPS configuration in step S324. According to the third SPSconfiguration which supports the third period, the CAM may betransmitted every 100 ms.

In step S325, a PUCCH is configured. A resource for the PUCCH may beexplicitly allocated from a PUCCH resource configuration. The PUCCHresource configuration may be included in the third SPS configuration.Alternatively the resource for the PUCCH may be implicitly allocated.For example, the resource for the PUCCH may be allocated x subframebefore the SPs resource of step S324. When a SPS period on a PUSCH or aPSSCH is changed due to activation of the third SPS configuration, evena period of the PUCCH resource is changed to fit the period of the SPSresource. Since the period of the SPS resource is reduced in step S324,even a period of the PUCCH resource is reduced accordingly. In stepS325, a PUCCH resource is allocated, and a PUCCH is transmitted usingthe corresponding PUCCH resource.

In step S326, whenever data transmission is allowed in a particular SPSresource grant, the UE transmits an ACK in response to the SPS resourcegrant using the corresponding PUCCH resource. Whenever there is no dataavailable in the particular SPS resource grant, the UE does not transmitthe ACK. If the eNB fails to receive the ACK continuously, the CAMgenerating period may be changed to a greater value in step S330. Instep S331, the UE transmits an SPS change request to the eNB. The eNBconfigures a PDCCH to be addressed to SPS C-RNTI#2 in step S332, andtransmits SPS release of the third SPS configuration and SPS activationof the second SPS configuration to the UE through the correspondingPDCCH. Having received the SPS activation of the second SPSconfiguration, the UE transmits the CAM through an UL or an SL using aSPS resource according to the second SPS configuration in step S334.According to the second SPS configuration which supports the secondperiod, the CAM may be transmitted every 500 ms.

FIG. 7 shows a method of performing an SPS operation by an UE accordingto an embodiment of the present invention.

In step S400, a UE receives an SPS configuration and a PUCCH resourceconfiguration from a network. The PUCCH resource configuration may beincluded in the SPS configuration. The SPS configuration may be a firstSPS configuration included in a plurality of SPS configuration, thePUCCH resource configuration may be a first PUCCH resourceconfiguration, and the plurality of SPS configurations may be includedin a second SPS configuration including a second PUCCH resourceconfiguration.

In step S410, the UE transmits an SPS change request to the network.Transmitting the SPS change request to the network may includetransmitting an SR to the network.

The UE receives an SPS resource grant activated based on the SPS changerequest from the network in step S420, and changes allocation of a PUCCHresource which has been allocated by the PUCCH resource configurationbased on the received SPS resource grant in step S430.

Changing the allocation of the PUCCH resource may include changing atiming of allocating the PUCCH resource as a timing of an uplinkresource or a sidelink resource to be allocated by the SPS resourcegrant is changed. Alternatively, changing the allocation of the PUCCHresource may include changing a period of allocating the PUCCH resourceas a period of an uplink resource or a sidelink source to be allocatedby the SPS resource grant is changed. The PUCCH resource may beallocated x subframe before a timing of an uplink resource or a sidelinkresource to be allocated by the SPS resource grant. Alternatively, thePUCCH resource may be allocated y subframe after a timing of receivingthe SPS resource grant.

The UE may transmit a message using an uplink resource or a sidelinkresource allocated by the SPS resource grant. The message may be any oneof the CAM, the DENM, and the BSM used in the V2X communication.

In the above-described embodiment of the present invention, an SPSchange/reactivation request, SPS activation, SPS release, SPS change inresponse to a change in an amount of L2 data equal to or greaterthan/equal to or smaller than a threshold value, an SPS period change,and an ACK/NACK in response to an SPS resource grant from the UE may beimplemented by the following options.

(1) PUCCH resource (e.g. SR)

(2) Transmission of random access preamble

(3) Transmission of message 3 including a C-RNTI MAC control element(CE) in a random access procedure

(4) Transmission of a random MAC CE (e.g. BSR, a power headroom report(PHR), a new CE)

(5) Transmission of uplink control information (UCI) in a PUSCH

(6) MAC CE piggyback in MAC PDU transmitted in PUSCH

The MAC CE in the above options may include an offset for the currentSPS start time, i.e. a time difference between the current SPS resourceallocation and resumed SPS resource allocation

FIG. 8 shows a wireless communication system to implement an embodimentof the present invention.

An eNB 800 includes a processor 810, a memory 820 and a transceiver 830.The processor 810 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 810. Thememory 820 is operatively coupled with the processor 810 and stores avariety of information to operate the processor 810. The transceiver 830is operatively coupled with the processor 810, and transmits and/orreceives a radio signal.

A UE 900 includes a processor 910, a memory 920 and a transceiver 930.The processor 910 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 910. Thememory 920 is operatively coupled with the processor 910 and stores avariety of information to operate the processor 910. The transceiver 930is operatively coupled with the processor 910, and transmits and/orreceives a radio signal.

The processors 810, 910 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 820, 920 may include read-only memory (ROM), randomaccess memory (RAM), flash memory, memory card, storage medium and/orother storage device. The transceivers 830, 930 may include basebandcircuitry to process radio frequency signals. When the embodiments areimplemented in software, the techniques described herein can beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. The modules can be stored inmemories 820, 920 and executed by processors 810, 910. The memories 820,920 can be implemented within the processors 810, 910 or external to theprocessors 810, 910 in which case those can be communicatively coupledto the processors 810, 910 via various means as is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

What is claimed is:
 1. A method for performing a semi-persistentscheduling (SPS) operation by a user equipment (UE) in a wirelesscommunication system, the method comprising: receiving an SPSconfiguration and a physical uplink control channel (PUCCH) resourceconfiguration from a network; transmitting an SPS change request to thenetwork; receiving an SPS resource grant activated based on the SPSchange request from the network; and changing allocation of a PUCCHresource, which has been allocated by the PUCCH resource configuration,based on the received SPS resource grant.
 2. The method of claim 1,wherein the changing allocation of the PUCCH resource allocationcomprises changing a timing at which the PUCCH resource is allocated asa timing of an uplink resource or a sidelink resource to be allocated bythe SPS resource grant is changed.
 3. The method of claim 1, wherein thechanging allocation of the PUCCH resource allocation comprises changinga period at which the PUCCH resource is allocated as a period of anuplink resource or a sidelink resource to be allocated by the SPSresource grant is changed.
 4. The method of claim 1, wherein the PUCCHresource configuration is included in the SPS configuration.
 5. Themethod of claim 4, wherein the SPS configuration is a first SPSconfiguration included in a plurality of SPS configurations, wherein thePUCCH resource configuration is a first PUCCH resource configuration,and wherein the plurality of SPS configurations comprises a second SPSconfiguration including a second PUCCH resource configuration.
 6. Themethod of claim 1, wherein the PUCCH resource is allocated x subframebefore a timing of an uplink resource or a sidelink resource to beallocated by the SPS resource grant.
 7. The method of claim 1, whereinthe PUCCH resource is allocated y frame after a timing of receiving theSPS resource grant.
 8. The method of claim 1, wherein the transmittingthe SPS change request to the network comprises transmitting ascheduling request (SR) to the network.
 9. The method of claim 1,further comprising transmitting a message by using an uplink resource ora sidelink resource allocated by the SPS resource grant.
 10. The methodof claim 9, wherein the message is any one of common awareness messages(CAM), decentralized environmental notification messages (DENM), orbasic safety messages (BSM).
 11. A user equipment (UE) in a wirelesscommunication system, the UE comprising: a memory; a transceiver; and aprocessor, operably coupled to the memory and the transceiver, that:controls the transceiver to receive an SPS configuration and a physicaluplink control channel (PUCCH) resource configuration from a network,controls the transceiver to transmit an SPS change request to thenetwork, controls the transceiver to receive an SPS resource grantactivated based on the SPS change request from the network, and changesallocation of a PUCCH resource, which has been allocated by the PUCCHresource configuration, based on the received SPS resource grant. 12.The UE of claim 11, wherein the changing allocation of the PUCCHresource allocation comprises changing a timing at which the PUCCHresource is allocated as a timing of an uplink resource or a sidelinkresource to be allocated by the SPS resource grant is changed.
 13. TheUE of claim 11, wherein the changing allocation of the PUCCH resourceallocation comprises changing a period at which the PUCCH resource isallocated as a period of an uplink resource or a sidelink resource to beallocated by the SPS resource grant is changed.
 14. The UE of claim 11,wherein the PUCCH resource configuration is included in the SPSconfiguration.
 15. The UE of claim 11, wherein the PUCCH resource isallocated x subframe before a timing of an uplink resource or a sidelinkresource to be allocated by the SPS resource grant.